Cancellation and outstanding funds

In the past months from June last year I have been asking cell c consultants to cancel my membership for my phone and they still haven't, they kept charging me until February this year where a couple of consultants kept calling me and I'll ask them to cancel the membership but they wouldn't.

I stopped paying un February which makes it 3 months and therefore today a lady from the collections department calls me yelling at me about my outstanding fee, I tell her she can take it but make sure I don't get charged again as I've been asking for people to cancel it. She tells me it's my fault that I didn't pay which I know however when she tells me I must pay for May which the service has been suspended since middle of May, please explain to me what am I paying for cos the phone us paid off .

I then called customer service as per collections lady , which they couldn't help me either one lady dropped my call and the other one quickly gave me numbers that didn't go through.

Someone please assist